Perhaps you should try some spelling variations:
"social effects models" » "special effects models", "social aspects models", "social effect models"
"social exact model" » "social effect model", "social etats model", "social email model"
"social et model" » "social en model", "social e model", "social etats model", "social net model", "social set model", "social jet model"

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: (((("social exact model") OR ("social et model"))) OR ("social effects models"))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"social exact model\") OR (\"social et model\"))) or (\"social effects models\"))*".
• Removing quotes may allow a broader search: (((( social exact model ) OR ( social et model ))) or ( social effects models ))*.